I think single women are having all the sex they want, but they are missing the intimacy they desire.
Any women can have sex and find a willing partner and fairly quickly, if they just make availability and willingness known.
However, it’s a lot tougher for a woman to find a partner that would care about them enough to invest in them because they care.
All recent polling has shown that the rates of sex among unmarried Americans (and even among married ones) is lower than it was a decade ago and far lower than it was back in the 80s-90s.
Oddly enough, it is lower among women than men which can be explained by the few women who are having sex are having sex with multiple men.
The one rate of sexual activity that has increased is what is called "rough" sex --choking, slapping, etc. Precisely the sex acts that are common in porn films.
We are a porn-drenched society and it shows and one place it shows is that people are satiating their sexual needs by watching porn rather than actively participating in sex. This is because young people, men in particular, do not know how to seduce women and no longer really care to learn. And when they try, they're vulgar and offensive because everything they think they know, they've learned from watching porn.